1. Technical Field
The present invention relates to liquid ejection head control methods and liquid ejection head control apparatuses.
2. Related Art
Liquid ejection heads and control apparatuses for controlling the liquid ejection heads are used in liquid ejecting apparatuses such as inkjet printers. These control apparatuses include a device that simultaneously generates a plurality of drive signals at a printing cycle, and selectively applies drive pulses contained in the drive signals to piezo elements in a liquid ejection head (see JP-A-2000-52570, for example). The selective application of the drive pulses is performed, for example, by applying waveform sections in the drive signals to the piezo elements at a timing prescribed by a latch pulse or change pulse (also referred to as a “channel pulse”) (see JP-A-H10-81013, for example).
In a case where the waveform sections in the drive signals are selectively applied to the piezo elements at the timing of the latch pulse or change pulse, noise may be generated in the drive signals. It seems that the noise is generated because the amount of current to the piezo elements suddenly changes. For example, in a case where waveform sections are applied to a large number of piezo elements, at the moment when the application is stopped all at once, the ground potential changes and the change may appear as noise in the drive signals. There is no problem when the noise generated in the drive signals is small, but excessively large noise may pose a problem for ejection of ink.